**Editor’s note: A previous version of this story said that four cases had been confirmed. APH updated their press release to clarify that the cases were investigated, not confirmed.

AUTIN (KXAN) — Heavy rainfall and floods can sometimes pose invisible threats on top of obvious ones. One of those is a heightened presence of mosquitoes, with which comes diseases and viruses they carry, like West Nile Virus.

During routine monitoring for mosquito-borne diseases, Austin Public Health identified a second positive mosquito pool for West Nile Virus in northwest Austin. Additionally, four human West Nile cases in Travis County have been investigated by regional case investigations.

The positive mosquito pool is located in the 78759 zip code. The first positive pool of the year was located last month in the 78721 zip code.

West Nile Virus is the most common mosquito-borne disease in the United States. It is typically spread to people by the bite of an infected mosquito. According to the Centers for Disease Control and Prevention, West Nile Virus is not spread through coughing, sneezing, or touching other people or live animals.      

According to the CDC, about 20% of people nationwide infected with West Nile Virus develop symptoms such as headache, body aches, joint pains, vomiting, diarrhea, or rash. Of those infected, few develop further serious illnesses affecting the central nervous system.

People over 60 years of age are at greater risk of developing serious disease, as are those with medical conditions such as cancer, diabetes, hypertension, kidney disease. Organ transplant recipients are also at risk for more severe forms of disease.    

“The Environmental Vector Control Program provides education, information and ideas on techniques that can be used by residents to mitigate or eliminate mosquitoes in the area,” said Marcel Elizondo, Interim Assistant Director for Environmental Health Services. “By removing standing water and using prevention tools we keep ourselves, our families and communities safe.”    

APH recommends the following steps and knowledge to prevent West Nile infection:

  • Drain standing water: Mosquitoes breed in standing water and need as little as one teaspoon. Emptying water that accumulates in toys, tires, trash cans, buckets, clogged rain gutters, and plant pots will deny mosquitoes a place to lay their eggs and reproduce.   
  • Dusk to Dawn: Although different species of mosquitoes are active at different times of day, the Culex mosquito that spreads West Nile Virus is most active between dusk and dawn.   
  • Dress: Wear pants and long sleeves when you are outside. Wear light-colored, loose-fitting clothing; mosquito repellent clothing is also available.   
  • DEET: Apply insect repellant: Use an EPA-registered repellent such as those containing DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol or 2-undecanone. Apply on both exposed skin and clothing.    

Mosquitoes are present in Central Texas year-round, but the population is largest and most active from May through November. During this period, the APH Environmental Vector Control Program monitors the mosquito population.    

In 2021, there were eight positive mosquito pools in Travis County and 1,515 positive pools across the state of Texas, and 77 confirmed West Nile virus cases.